Campaigners opposed to genetically modified crops have warned that they will destroy any further trials planted in Scotland.

The threat was made as they handed over a 5,000-signature petition to the Department for Environment, Food and Rural Affairs (Defra).

Protesters who set off from Munlochy in the Scottish Highlands on Monday were joined by campaigners from other parts in the UK at the demonstration in London.

Doing these experiments in an open environment is simply a recipe for contamination

Donnie MacLeod Campaigner

Sacks of GM crops which had been ripped up from trial sites across the country were dumped outside the government building on Wednesday.

The protest was staged as the Scottish Executive published proposals for tighter regulations of the trials north of the border.

The campaigners who handed over the petition in London included Donnie MacLeod, an organic farmer who was jailed for refusing to identify campaigners involved in damaging a field of oil seed rape near Munlochy.

He said: "Doing these experiments in an open environment is simply a recipe for contamination.

"If nothing goes wrong then they are very lucky, but at the end of the day if something does go wrong how are they going to get the genie back in the bottle?"

'Selfish ends'

The seeds are due to be sown soon for two new Scottish trials in Fife and Aberdeen.

However, the UK Government has insisted that the trials are safe.

Former Scotland Office minister George Foulkes said: "I am in favour of safeguards and the Scottish Executive and the government are bringing those in.

Modified oilseed rape is arousing concerns

"But that will not satisfy the protesters. They are totally against these trials.

"They are willing to break the law; they are willing to sacrifice the huge potential benefits for their own selfish ends."

The Scottish Executive consultation document proposes a stricter system of regulation of genetically modified organisms (GMOs).

The suggested reforms also seek to make the system more easily understood by growers and the public.

Views are being sought before MSPs consider legislation in the autumn.

Scientific scrutiny

Similar legislation is being proposed across the UK, after the recent strengthening of a European directive on GM crops.

The Scottish Executive said the proposed rules would make it compulsory for public views to be sought on applications to grow GM crops - so far, this has been voluntary.

The new rules would also ensure tougher scientific scrutiny of applications.

Protesters targeted the Defra building

There would be a further requirement for long term monitoring, and genetically-modified organisms, which are allowed to be used commercially, would need to be monitored for unexpected effects on the environment.

An executive spokesman said: "Along with the other proposed changes, these measures are intended to produce a regulatory system which can be more readily understood by both potential applicants and the public alike.

"Each stage of the process will be transparent with information made available to the public on the release and marketing of GMOs."

The spokesman said much of what was already happening in Scotland, like having a public register of GMO releases, had been introduced voluntarily in advance of the new regulations.

He said: "The new legislation will therefore place many current practices on a statutory rather than voluntary footing."